Apparatus for the control of the ingition of internal combustion engines



June 22, 1943. F, H F-0 D ETAL, 2,322,690

APPARATUS FOR THE 'coN'rRoL OF THE IGNITION v OF INTERNAL COMBUSTION ENGINES Filed July 21, 1942 Patented June 22, 1943 APPARATUS FOR THE CONTROL OF THE IGNITION OF INTERNAL COMBUSTION ENGINES Fr-ank Bernard Halford, Edgware, and Adrian Leslie Catford, Hampton, England, assignors to D. Napier & Son Limited, London, England, a company of Great Britain Application July 21, 1942, Serial No. 451,790 In Great Britain September 5, 1941 7 Claims.

This invention relates to apparatus for the control of the ignition in an internal combustion engine and particularly when the engine is mounted in an aircraft and has for its object to provide means whereby under certain circumstances or conditions this control may become automatic.

According to this invention variations in the ignition timing are effected alternatively either by movement of a hand lever or automatically by movements derived from a capsule which is sensitive to variations in fluid pressure, the changeover taking place automatically when and continuing while the throttle is opened fully. The hand lever is automatically rendered inoperative on the ignition control when the throttle has been opened fully and there is brought into action the pressure sensitive capsule which then operates automatically to vary the timing. The movements necessary to effect variations in the ignition timing are transmitted through a cam inember of which one part functions to transmit movements from the hand lever While this lever is operative to vary the timing, the other part of the cam member serving to transmit movements from the capsule when this has taken over the control of the timing. There is combined with the throttle operating mechanism means whereby when the throttle has been opened fully this mechanism will automatically cause an interruption in the means by which the hand lever transmits the movements necessary to vary the timing thus'leaving the capsule free to take over the control of the ignition timing.

The apparatus thus comprises in combination one or more magnetos and one or more distributors with means by which they are driven and for adjusting them to vary the ignition timing, a cam-shaped lever by movement of which this adjustment is eflected, a pressure-sensitive cap- 's'ule, a hand lever with means by which it can move the engine throttle, a member engaging the lever cam and movable both by the capsule and by the hand lever, and means brought into action by the throttle operating mechanism when the throttle is opened fully for preventing the hand lever from transmitting movements through the lever cam on which the capsule is then free to act and thus take over the control of the ignition timing. Conveniently the move- "ments necessary for the control of the ignition are superimposed through a diiferential or like gear on the shafting through which the distributor and magneto are normally operated. The accompanying drawing Figure 1 is a diagrammatic perspective view showing by way of example how the invention may be carried out in practice. Figure 2 is a detail showing a modification having two magnetos and two distributors.

A hand lever A on a suitably arranged rotatable shaft A is connected to the engine throttle. This connection may be by way of one arm B of a bell-crank lever from which extends a rod C to a lever D on the spindle D which carries the throttleD From the second arm B of the bell-crank lever of the hand lever A extends a connection E to the one arm F of a bell-crank lever whose fulcrum F is carried by a rod G projecting from a piston G which is movable in a cylinder G 'against the action of a spring G From the end of this cylinder G which is at the side of the piston G remote from the spring G runs piping H to a casing H in which is a valve J adapted to be moved in the cylindrical casing H when the end of a projection J from the valve comes into contact with the throttle lever arm D. This will be when the hand lever A has moved the throttle D into its fully open position. The valve J will then be moved against the spring J by the lever D which will be in the position shown in dotted lines, and will establish connection between a supply of fluid under pressure which can enterthe valve casing H through the port H and the piping 1-1.

This pressure fluid entering the cylinder G will move the piston G against the spring G and thus alter the position of the fulcrum F of the lever F. If the throttle is now partially closed the valve J will be released and will be moved by the spring J 2 into a position wherein the piping H through the valve casing H will be placed in communication with the exhaust port H By thus relieving the fluid pressure that Was acting on the piston G the latter will be moved back to its initial position by the spring G3 'restoring the lever fulcrum F to its previous place. The pressure fluid thus employed may be oil under pressure drawn from the lubricating oil circuit of the engine.

A pressure-sensitive capsule K is disposed in a casing L in which the whole capsule can move, the interior of the casing being in communication with the atmosphere so that the capsule can be acted on by variations in the atmospheric pressure. From one end of the capsule, which as shown in the drawing is its upper end, projects a rod K on the end of which is an enlargement K adapted to function as a stop to limit the movements of this end of the capsule, this enlargement lying and moving in a cylinder L A spring K acts on this same upper end of the capsule tending to move it downwards. At-

7 tached to and extending from the other or lower end of the capsule is a spindle M which can slide in guides L in the enclosing casing L. Projecting laterally from this spindle M is a pin M which lies in engagement with twin cam slots N formed in a lever N movable about the fulcrum N In the form shown each of these slots N is somewhat Z-shaped with the central or intermediate part W lying at an angle to the two end portions of the slot. It will be seen that sliding movement imparted to the spindle M will swing the cam lever NN about its fulcrum N and this will move in a known way the valve of a servo device enclosed in the casing O. The

' lower end M of the spindle M lies in contact with, but is not connected to the end of the second arm F of the bell-crank lever whose other arm F is connected to and moved by the hand lever A. This lever FF and its fulcrum l? are so arranged in relation to the end M of the spindle M that when there is no pressure fluid in the piping H to act on the piston G the spring G3 can maintain this piston and the fulcrum F in their raised or more normal positions, and the end of the lever arm F will remain in contact with the end M of the spindle. So long as this state of things continues the hand lever A when it is moved to alter the setting of the throttle D will slide the spindle M and through the pin M swing the servo valve lever NN Sliding of the spindle M in the one ordownward direction will be due to the spring K acting through the capsule K which as a whole will then move with the spindle. Movement of the latter in the opposite or upward direction will be due to movement imparted to the bell-crank lever FF by the hand lever A.

Consequent on a setting of the servo valve by the cam lever NN the shaft P carrying a toothed quadrant P will be turned and since this quadrant meshes with the toothed quadrant Q on the shaft Q this shaft also will be turned through a corresponding angle. A lever on this shaft Q acting through a link Q will then swing a cage Q carrying a bevel pinion Q about the shafts R and S will be altered and thus the timing of the ignition will be varied. This will result from a setting of the valve of the servo by movement of the cam lever NN in accordance with the movements imparted to that lever either from the hand lever A or, when the throttle has been opened fully, from the capsule K.

In Figure 2, there is shown a modification wherein the control mechanism is applied to an arrangement having two distributors, T and two magnetos, U the shaft, S and driving gear S being the corresponding elements shown in Figurel.

During running and with partial openings of the throttle by the hand lever A the connection from that lever to the sliding spindle M will be operative and variations in the ignition timing will be effected as the throttle is moved.

When, however, the throttle has been opened fully, the lever D will act on and move the valve J and allow pressure liquid to pass into the one end of the cylinder C: with the result that the piston G will be moved against the action of the spring G. This will lower the whole lever F, F B into a position wherein the end of the lever arm F can no longer act on the end of the spindle M and in this way the hand lever A is rendered inoperative on the ignition timing mechanism. The control of the timing is now taken over by the capsule K and according as this expands or contracts, due to fluctuations in the atmospheric pressure, so will the servo valve be set by swinging of the cam lever NN and variations in the timing will be effected. During the time that the hand lever is operative to control the timing the pin M on the sliding spindle M will lie and move in the one end part of the twin slotted links N, but when the change-over occurs this pin M will pass through the centre portion of the cam links N into the other end part of the cam lever. If now the hand lever is moved so as to partially close the throttle the valve J will be freed to be acted on by the spring J and moved into such a position that the piping H will be placed in communication with the drainoff 1-1 for the pressure liquid. The relief of the pressure from the one side of the piston G will permit the spring G to restore the piston and the lever FF carried by it to their initial positions wherein the lever arm F can again act on the end of the spindle M and once more take over control of the timing.

If the cam lever happens to be formed as shown with Z-shaped slots in the twin links, the pin M will pass through the centre part N in these links during or at the change-over. The slotted links may, however, be otherwise shaped and there may be a smooth transition of the pin M from the one end portion of the links into the other end part. Thus each link may follow a continuous curve or a more or less straight line without any such intermediate interruption in the continuity of the slot such as i the part N It will be appreciated that means other than those more particularly described above may be employed for the purpose of automatically rendering the hand lever inoperative on the ignition control when the throttle is fully open.

The means by which the variations in the timing of the ignition are effected through a differential gear as indicated above may be on known lines.

What we claim as our invention and desire to secure by Letters Patent is:

1. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means for driving them, a pressure sensitive capsule, an engine throttle, a hand lever and means for moving the throttle by this lever, means for adjusting the magneto and distributor to vary the timing by movements transmitted through a cam member, means by which the hand lever can act on this cam member, means by which the said capsule can act on the said cam member, and means whereby when the throttle is opened fully the capsule automatically becomes operative alone on the said cam member and controls the ignition timing and simultaneously the hand lever ceases to act on the said cam member until the throttle is at least partially closed.

2. In apparatus for the control of the ignition in an internal combustion engine as set out in claim 1, a cam member through which the movements are transmitted to vary the timing with means whereby one part of this cam member is acted on by the hand lever and another part is acted on by the said capsule when the latter is permitted to become operative and the hand lever has been rendered inoperative to vary the timing.

3. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means by which they are driven and means for adjusting them to vary the ignition timing, a pressure sensitive capsule, an engine throttle, a hand lever and means for mov ing the throttle by this lever, a member movement of which brings about the adjustment necessary to vary the timing, means by which movement can be imparted to this member and control of the timing effected by the said hand lever, means by which movement can be alternatively imparted to this member and control of the timing effected by the said capsule instead of by the hand lever, hydraulically actuat'ed means which determined whether the timing shall be controlled by the hand lever or by the capsule, and a valve controlling such 11ydraulic means and actuated by the throttle operating mechanism so as to cause the change over :2

to take place automatically when and to continue while the throttle is open fully.

4. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means by which they are driven and means for adjusting them to vary the ignition timing, a pressure sensitive capsule, an engine throttle, a hand lever and means for moving the throttle by this lever, means comprising a servo device operative to effect the adjustment of the magneto and distributor necessary to vary the timing, a cam member movement of which determines the operation of the said servo device and brings about variation in the ignition timing, a control member which when moved will act on and move the cam member, means by which this control member can be acted on and moved by the hand lever, means by which the said control member can be acted on and moved by the said capsule, hydraulically actuated means which determine automatically whether the timing shall be controlled by movement of'the hand lever or by movement derived from the capsule, and a valve controlling such hydraulic means and actuated by the throttle operating mechanism so as to cause the change over to take place automatically when and to continue while the throttle is open fully.

5. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means by which they are driven and means for adjusting them to vary the ignition timing, a pressure sensitive capsule, an engine throttle, a hand lever and means for moving the throttle by this lever, means comprising a servo device operative to efiect the adjustment of the magneto and distributor necessary to vary the timing, a cam member movement of which determines the operation of the said servo device and is constituted by a lever in and along which runs a slot, a control member which can slide in guides and has a part which engages the said slotted lever, means by which this sliding control member is acted on at one end by the said capsule and at the other end is engaged and acted on by mechanism operated by the hand lever, and hydraulically actuated means operative automatically to inhibit action by the hand lever on the said sliding control member when the throttle has been opened fully and While it remains fully open.

6. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means by which they are driven and means for adjusting them to vary the ignition timing, a pressure sensitive capsule, an engine throttle, a hand lever and means for moving the throttle by this lever, a member movement of which brings about the adjustment necessary to vary the timing, mechanism by means of which movement is transmitted from the hand lever to the said member which varies the timing, hydraulically actuated means by which a part of this transmission mechanism from the hand lever can be moved from an operative into an inoperative position when the hand lever will be prevented from varying the timing, means by which movement can be imparted to the said member which varies the timing by the capsule when the hand lever is prevented from doing so, and a valve controlling the operation of the said hydraulic means and actuated by the throttle operating mechanism whereby the hand lever will be automatically prevented from acting on the said member which varies the timing when the throttle is open fully and while it continues to be fully open.

'2. In apparatus for the control of the ignition in an internal combustion engine the combination of at least one magneto and at least one distributor with means by which they are driven and means for adjusting them to vary the ignition timing, a pressure sensitive capsule, an en gine throttle, a hand lever and means for moving the throttl by this lever, means comprising a servo device operative to effect the adjustment of the magneto and distributor necessary to vary the timing, a cam member movement of which determines the operation of the said servo device and is constituted by a lever in and along which runs a slot, a control member which can slide in guides and carries a part which engages the said slotted lever, means by which this sliding control member is acted on at one end by the said capsule, mechanism by means of which movement is transmitted from the hand lever to the other end of the said sliding control member, hydraulically actuated means by which a part of this transmission mechanism from the hand lever can be moved from an operative into an inoperative position when the hand lever will be prevented from moving the said sliding controlmember and thereby varying the timing and this can then be effected only by the action of the capsule on the said control member, and a valve controlling the operation of the said hydraulic means and actuated by the throttle operating mechanism whereby the hand lever will be automatically prevented from varying the timing when the throttle is open fully and while it continues to be fully open.

FRANK BERNARD HALFORD. ADRIAN LESLIE CA'IFORD. 

